$1\mathrm{.}5$ Thabo was using a single effect evaporator to concentrate

$10$ wt$\%$ sugar solution into syrup of $30$ wt$\%.$ Saturated

steam is used as a heating medium and is supplied at a

particular pressure. This evaporator used a water$-$cooled

condenser to condense the vapor produced in order to keep

the evaporator pressure at the desired value. One day after

some time of running the evaporator, he comes to find that

the evaporator is only able to achieve $20$ wt$\%$ at the

conditions he has been using. He wants to embark on

troubleshooting but he does not know what to look. Explain

to Thabo eight things he should investigate and tell him how

he can correct each in order to have the evaporator giving

him the desired final concentrate